RMS or Peak?...what to go by?

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coolsoundman

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Ok, I think there is a thread out here somewhere talking about the RMS and the Peak value on the meters and they are too jargonsm to understand. In plain english, what should I I go by, the RMS or the Peak value? When I do my playback, the peak value is high, somewhere around +6 or more, but the RMS is still very low, somewhere around -15. The music doesn't sound distorted, just a little loud. But, when you put it on cd and play it on a stereo, you have to turn the volume control a little bit higher than a regular cd that is made in the industry. So that is my question, what should I go by, the RMS or the Peak meter?
 
go by Rms man. My dad explained to me in the complicated way, and all i remember was rms is what really counts. peak to peak is dealing with negative and postive values of some sort, shagsdgaedufaeriserogs, and other nonsence. im not sure if that helps man, but if your recordings are low, master them. hope that helps. Flame
 
RMS = root mean square. Simplified, it refers to the average volume level. A low RMS is why your stuff doesn't sound as loud as a commercial CD. This is normally adjusted in mastering.

Peaks are what you would think the mean, the highest level reached at a given point in time.

Generally for your master bus you should always peak below zero. Zero is where digital clipping occurs. In fact, you should keep them even lower than that (-6 to -3 db) in order to leave some headroom for the mastering engineer.
 
I use peak for recording, and peak + rms for playback.

watching the peak meter gives you a good visual for where you may need to set your compressor threshold to tame the peaks.

watching the rms meter gives you a good visual for where that track is sitting in the mix.

Those peaks will be the overs that you have to smash with your maximizer when you are later trying desperately to get your CD to sound loud like the pro CDs so the closer your peak and RMS levels are (without ruining your dynamics) the better off you'll be when the track is mixed.
 
RMS level is, more or less, what you percieve as volume. Peak just measure that transients. On a percussive track, you could have very high peaks but low rms levels.

Commercial CDs, depending on genre, will be anywhere from -12db to -8db rms. All of them will have peak levels just under 0db. This volume comes from mastering. If your mixes are sitting at -15, that is actually pretty loud for a pre-mastered mix.

To answer your question, it depends on what you are doing.
For recording: Set the level so your RMS level is about -20, making sure your peak level doesn't hit 0dbfs. With things like drums, just make the peak around -6dbfs, the rms level will be very low on these instruments.

For mixing: This should take care of its self, just don't go over 0dbfs.

For mastering: I like to hit -12dbFS RMS and about -0.3dbFS for peak.

You have to watch both.
 
The Flame said:
My dad explained to me in the complicated way, and all i remember was rms is what really counts.
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I'm an electrical engineer by profession and I'm sorry, but what your dad told you is just not true. RMS does count and it's very important not to have your RMS levels too low or too high, but it's more important to have your peaks below 0dB.

dachay2tnr said:
RMS = root mean square. Simplified, it refers to the average volume level. A low RMS is why your stuff doesn't sound as loud as a commercial CD. This is normally adjusted in mastering.

Peaks are what you would think the mean, the highest level reached at a given point in time.

Generally for your master bus you should always peak below zero. Zero is where digital clipping occurs. In fact, you should keep them even lower than that (-6 to -3 db) in order to leave some headroom for the mastering engineer.
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dachay2tnr is completely right. And mastering will get the levels all to an RMS usually somewhere between -6dB and 0dB for commercial CDs. Digital clipping is very bad for the sound. You'll hear pops and "static" at the points where your sound level goes above 0dB and you can't smooth it out.

Fairview said:
Commercial CDs, depending on genre, will be anywhere from -12db to -8db rms. All of them will have peak levels just under 0db. This volume comes from mastering. If your mixes are sitting at -15, that is actually pretty loud for a pre-mastered mix.
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I'm not sure I completely agree with this, but it certainly isn't wrong.

I personally mix my songs to -12dB to -6dB pre-mastering and then when mastered (either by me or a mastering engineer) usually get bumped up to -6dB to 0db (ceiling - in other words, approaching 0dB, but never reaching it).
 
You are confusing peak and rms in your measurments. There is no way to get an RMS reading of 0db unless you recorded DC, 20 db above line level.

The meters in your daw read peak, not rms. I think you are getting confused between where your average peaks land and the actual RMS level of the signal.


Getting something to average at -9dbfs is very hard to do without destroying the sound of it.
 
I'm sure you've heard the phrase "peak meters respond better to transients" but if you feel that's too jargony for you, look at it this way: As has been said VU (volume unit) meters show an average (RMS) voltage.

But the important part, in my mind, is that VU meters are more representative of how the human ear actually hears. That's a pretty simple way to understand the difference without any technical terms.
 
Farview said:
The meters in your daw read peak, not rms. I think you are getting confused between where your average peaks land and the actual RMS level of the signal.
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Most DAWs (I know Sonar does) allow you to switch between VU, Peak, or VU+Peak.
 
RAK said:
Most DAWs (I know Sonar does) allow you to switch between VU, Peak, or VU+Peak.
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And is it possible to get a VU reading of 0dbfs? 0dbVU? Sure, but that would translate to -20dbfs RMS. You have to watch the scales. The scale on a vu meter is different than that of a peak meter. So, in Sonar, is it a VU meter with a VU scale? Or is it just a meter with VU ballistics using the dbFS scale?
 
Ah, meters! Worth learning to understand the jargon about.

In general though, peak when tracking then peak and rms when mixing.

Peak is most important when tracking to a DAW. You *never* want to peak above 0dBFS (full scale)- clipping the convertors doesn't sound good at all. I think that's the only reason peak meters are so common these days and everyone is confused about rms.

When mixing, you don't want any clipping either so you have to watch your peaks, but rms readings will more accurately reflect what your ear is hearing.

That's the short of it. Accurate metering hardware is expensive and metering plugs take a fair amount of overhead if you use them on every track- which I sometimes do and just disable them when I'm not looking at them.

I'm kind of a geek about it though. I started on analog as a kid and missed real VU meters so I bought an old Tascam mixing board with a bunch of VU meters in it. Happiness. 12 VU meters with peak lights. :D Less expensive than one stand alone box with 4 meters in it... but probably way less accurate, too, and certainly harder to adjust.

Farview's question about VU ballistics is spot on, too. Are you sure the "rms" meter is true rms and not just peak metering slowed down to act more like rms? It doesn't really matter (ears, use your ears) but I'd check the documentation and find out just so you know what you're dealing with.

Have fun! This is some the "engineering" part of being and audio engineer. Good stuff.
Chris
 
To be honest, I don't know how Sonar or any other DAW calculates its RMS or Peak meters. Personally I don't really pay attention to DAW meters anyway. You can clip those and it isn't really going to harm anything. If the DAW is all you've got though, then you would want to watch them I suppose.

I definetly see what you're saying about "true rms" but never investigated what Sonar means by that claim. Usually I just like seeing the two levels bouncing at the same time, it's fun.

I think it's more important to calibrate your system with an SPL meter so you know what your actual dB level output is. If you know you're putting out 85dB (or whatever) with Faders set to Unity Gain, then you're set. If you hear any digital clipping, turn it down.
 
Hey Fairview,

I was in St. Charles a few weeks ago teaching a course in Technical Architecture. Went to the mall and got a Hollister t-shirt, went to Al Capone's steakhouse and got my grub on, and then went to the cadillac ranch and got my groove on.
 
crosstudio said:
Hey Fairview,

I was in St. Charles a few weeks ago teaching a course in Technical Architecture. Went to the mall and got a Hollister t-shirt, went to Al Capone's steakhouse and got my grub on, and then went to the cadillac ranch and got my groove on.
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That is just about everything you can do here, short of going to Colonial cafe and eating a kitchen sink. (a dessert with 10 scoops of ice cream, 6 toppings, bananas, etc... served in something that looks like a sink)
 
Didn't see you were from Illinois. I think I worked a gig out in St. Charles a year or so ago. That's where Accenture is right?
 
RAK said:
That's where Accenture is right?
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Never heard of it, but that doesn't mean much. I spend most of my time in this windowless room listening to the same song over and over again.
 
Accenture use to be part of Arthur Anderson I guess. They have this huge corporate retreat campus (I'm pretty sure it was St. Charles). I was out there for a week as part of a crew putting their show together. I just remember it was a long drive from the city.
 
Depending on where you are in the city, it's only an hour. St. Charles is on North Avenue about 35 miles west of the city. Dead center between Elgin and Aurora.
 
yeah, that's definetly where I was. Glad we figured this out. It was really integral to the RMS/Peak debate. :)

(sorry to derail the post)
 
Accenture owns it but lets other companies use it too. they bring recent grads from all over the world there for 2 weeks of core analyst training. its the best smorgasbord of young, beautiful and intelligent skirts you'll ever see outside of the house/senate interns that come to DC every year.

and them foreign youngsters can hold their liquor.
 
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